You'll have to cut and paste this link as my iPhone doesn't like the 'add a link' feature. This is a brief article on the impact of and how to minimize the effects of anti-biotics on our kidneys.
If your back is hurting and you are having trouble peeing, I suggest you get your butt right over to your doctor's office and have them make sure something very serious is going on! This is not a situation that should ever be guessed at or self-diagnosed. You could be contributing to your kidney functions.
That said, cranberry juice is a good preventative step as it helps your kidneys flush themselves more easily. It's also helpful when you've been diagnosed with a urinary tract infection.
Pomegranate is on my limit/avoid list per my renal dietition. Not a good thing to use with any frequency. Hope this helps some!
Those who think they have no time for a healthy lifestyle will sooner or later will have to find time for illness.